Assessment of Hydrological Trends and Changes in Hydroclimatic and Land Use Parameters in a River Basin in Northeast Brazil

The hydrological effects of land use change are difficult to differentiate when changes are slow and hard to isolate when climate variability is also present. The study aims to evaluate the effects of climate variability and human activity on the flow in the Cachoeira River Basin. For this purpose, classical tests were used to identify trends and measure the strength of association between two variables, as well as the Rainfall Anomaly Index (RAI) and the Budyko Curve Decomposition were applied to the study so that it could verify the behavior of precipitation and the quantification of anthropic impacts and climate variation in the basin. In addition, the Indicators of Hydrologic Alteration (IHA) software was used to identify hydrological changes in the basin as a function of time. The results show a significantly decreasing trend for the forest and a significantly positive trend for pasture class and temperature. Correlation analysis indicated that changes in flow rate are correlated with precipitation, however, anthropic factors must be potentiating the impacts of climate variations as shown in the period 1991–1995 and 2011–2015. Finally, the hydrological indicators of the Cachoeira River Basin showed significant changes, which may compromise the flows in the long term if anthropic factors continue to enhance the climatological factors.